1. Field of the Invention
The present invention relates generally to Near Field Communication (NFC) and, in particular, a peer-to-peer communication method for Near Field Communication (NFC) to provide the required link-level security to an NFC terminal during peer-to-peer communication.
2. Description of the Related Art
NFC technology evolved from a combination of contactless identification (RFID) and interconnection technologies. It integrates a contactless reader, a contactless card, and a peer-to-peer function on a single chip and operates in the 13.56 MHz frequency range, over a distance of typically a few centimeters. NFC technology is standardized in International Standard Organization/International Electrotechnical Commission (ISO/IEC) 18092, ISO/IEC 21481, European Computer Manufacturers Association (ECMA) 340, 352 and 356, and European Telecommunication Standards Institute (ETSI) TS 102 190. NFC is also compatible with ISO/IEC 14443A-based contactless smart card infrastructure, i.e. Phillips MIRAFE® technology as well as Sony's Felica card.
NFC peer-to-peer communication provides a communication channel between NFC-enabled devices to exchange data in a point-to-point communication manner. That is, the devices exchange data on an equal basis without complex setting.
FIG. 1 illustrates a conventional NFC protocol stack. As shown, a Radio Frequency (RD) layer 100 is the lowest layer and complies with ISO/IEC 18092 and 14443B for NFC. The RF layer 100 corresponds to a physical layer in an Open Systems Interconnection (OSI) reference model and performs data modulation and demodulation as well as radio transmission. A Logical Link Control Protocol (LLCP) layer 110 is responsible for link management, segmentation and reassembly, and connectivity to a plurality of upper-layer protocols. An existing stack layer 120 refers to a variety of existing transport layers including, for example, Transmission Control Protocol/Internet Protocol (TCP/IP) and Object Exchange (OBEX). An NFC Data Exchange Format (NDEF) layer 130 defines a common data format for NFC Forum-compliant devices and NFC Forum-compliant tags. An application layer 140 refers to general execution programs.
FIG. 2 is a diagram illustrating an exemplary signal flow for a conventional message exchange procedure for NFC peer-to-peer communication, particularly a process for providing security functionality. Referring to FIG. 2, an initiator terminal 200 and a target terminal 210 are shown as NFC Forum-compliant devices. The initiator terminal 200 initiates a peer-to-peer communication, and the target terminal 210 is the receiving party of the peer-to-peer communication.
Both the initiator terminal 200 and the target terminal 210 have the protocol stack architecture illustrated in FIG. 1. Hence they have their respective application layers 201 and 211. After setup of the peer-to-peer communication, the initiator terminal 200 exchanges data with the target terminal 210 at the application layers 201 and 211 without a link-level security in step 220. If the application layers 201 and 211 provide the application-level security, key generation and exchange are performed through a security manager (not shown).
Examples of the NFC technology illustrated in FIGS. 1 and 2 are found in Korea Patent Application No. 2005-7010453 entitled “Communication System, Communication Apparatus and Communication Method” filed on Jun. 9, 2005 (US2006-6245402, PCT/JP03/15646).
However, the conventional NFC peer-to-peer communication illustrated in FIGS. 1 and 2 does not provide a link-level security for protecting the exchanged data. Therefore, confidential user data cannot be protected with the link-level security. Although an upper-layer protocol may provide the security functionality, a higher-level security requires the link-level security functionality that encrypts data at a data link layer (an OSI reference model) for transmission.